It's sad. I have a big client who uses this extension for more than 6 years and now has to change a code base of 500,000 lines of code or install an old version of PHP in the new server. They recently bought a redundant, double cpu, 8 gb ram, scsi disk server and will not be happy to run old versions of software with unmaintained extensions.

Installation on RedHat Fedore Core (or in that matter any Linux OS which has a version of glibc of 2.3.* ~or above~) will need to have the latest Informix CSDK (downloadable from IBM). 2.90.UC1.LINUX at the time of this post.

I was unable to make PHP with v2.80 of the csdk (as it complained about mktemp being dangerous and how ctype was undefined. After downloading csdk 2.90, I was able to make PHP with no problems at all. (--with-informix).

There goes 2 days of my life!

Feel free to drop me an email at ian_at_devtonic_dot_com if you have any questions.

I upgraded to csdk-2.70.UC3-1 and got the following error when trying to start apache:

Syntax error on line 205 of /usr/local/apache/conf/httpd.conf:Cannot load /usr/local/apache/libexec/libphp4.so into server: /opt/informix/lib/esql/libifgen.so: undefined symbol: stat/usr/local/apache/bin/apachectl start: httpd could not be started

This machine has glibc 2.3.5

The following fixed the problem for me (surely there's a better fix) but i'm not sure how it might affect other programs linked to libifgen

I have compile php-4.0.6 with informix support (dynamic) and when I try to start apache, it gives me this error message:

Syntax error on line 246 of /etc/httpd/httpd.conf:Cannot load /usr/lib/apache/libphp4.so into server: /home/informix7/lib/esql/libifgen.so: undefined symbol: stat/usr/sbin/apachectl start: httpd could not be started

If you are tring to access an Informix Online 5.x server over the
network (ie from a webserver) using PHP, be aware that Online
doesn't support network communications as standard unlike later versions.

You need the Informix product 'I-Star' on your Online server.
This will allow your webserver with the informix client SDK
installed to communicate natively (ESQL).

There's also a FreeBSD version of the client libraries that'll work with PHP. It's not available for download from their website, but you can request a copy (cd or electronic delivery) by calling Informix Customer Support at 1-800-274-8184 option 3.

Some customer service reps know more about alternative operating systems than others, so you may have to do a bit of educating before they can locate the product in their database, but it's definitely there.

My e-mail confirmation referred to it as "Orderable Part Number 100-15871-204057-1", although that number may be specific to the electronically-delivered edition.

I just wrote a mini-HOWTO about adding Informix support to mod_php running on a Gentoo Linux server (x86). I wanted to post it here but it was too long. You can find it on http://forums.gentoo.org/viewtopic.php?t=245249 (just in case for some reason they change the thread number, the title is "HOWTO: PHP Informix client support").